I spoke to a prospective PhD advisor who would like me to apply to his program. He made it clear that admission is not guaranteed, but since our general interests align, he suggested I apply. He said he would be interested in working with me, since my previous research is complementary to his current work, and I worked with his research advisor. I also really like the direction of his research and see myself working in that domain.
However, I have now changed my mind about applying to the program (deadline is in a month) because I am going through mental health issues and I do not feel prepared to apply. I also initially wanted to apply after an undergraduate degree. But now, I want to finish my Master's program before I apply (I am currently in the first year of a 2 year program) since the MSc will help bolster my application, especially because it's a competitive program and I have a non-traditional background. It was a difficult decision but I believe it is the right one.
How do I let the professor know this without souring my relationship with him (since I really would like to work with him, just not now, and I would like to emphasize this)? I have had a meeting with him and his grad student, and I don't want it to seem like I wasted their time. How common is it for meetings with prospective students to not lead to applications? I also feel it's a bad idea to be explicit about my mental health struggles (not that he isn't a nice person), so I don't know how much detail I can go into.
